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2018 Annual Report on Geothermal Exploitation for the Netherlands released

Geothermal energy based heat production in the Netherlands 2007-2018 (source: Nlog.nl)
Alexander Richter 19 Aug 2019

The Ministry of Economic Affairs in the Netherlands published its annual report on resource exploitation in 2018, including a geothermal section providing details on the level of geothermal energy utilisation in the Netherlands.

This July, the Ministry of Economic Affairs in the Netherlands published their annual report on resource exploitation in 2018, including a geothermal section. The reports shows dynamic licencing activity In 2018, with 9 new geothermal exploration licences being granted, 5 licences that expired and 15 that were extended. In total, 51 exploration licences and 9 production licences have been granted before 1 January 2019. The report also shows that 2019 is likely to witness a significant expansion of the number of exploration and production licences, with some 20 new applications being processed at the moment.

With three news wells that were drilled in 2018, ECW Netwerk became the largest geothermal operator in the Netherlands. Other noticeable developments were new drillings to the both the shallowest geothermal aquifer so far as well as to the deepest geothermal target. The shallowest geothermal aquifer that has so far been targeted in the country lies below Zevenbergen. A new doublet with a depth of 700 to 800 m aims to exploit the Eocene Brussels Sand Member and has a testing phase in June this year. The deepest exploration to a 4 km deep Triassic aquifer below Naaldwijk proved to be unsuccessful because of complete cementation of the pore space. Fortunately, the well planning included a smart back-up option, allowing perforation of a shallower aquifer section, which is a prolific aquifer in most geothermal projects in the region. The wells are currently in operation producing approximately 20 MWth of heat. Additional wells are planned in Naaldwijk to expand production further, according to the Trias Westland news feed.

In total 24 deep geothermal doublets have been realised in the Netherlands before 1 January 2019. 2 doublets were taken temporarily out of production in May and August 2018, respectively, after a seismic event with a magnitude 1.7 near one of the projects. The State Supervision of the Mines (SodM) reports in their annual review 2018 (published in May 2019) that production still remains on hold until sufficient scientific evidence can be provided that exploitation could resume safely.

In 2018, the total geothermal heat production from all active Dutch doublets ranged from some 110 to 160 TJth per month, adding up to a total of 3.67 PJth per year. This is almost 0.7 PJth­ more than last year (see ThinkGeoEnergy article form one year ago). Along with this heat, almost 11 million Normal cubic meter (Nm3) of natural gas was co-produced. Most of the doublets exploit sedimentary aquifers in mature oil and gas basins and as a result, dissolved gas is present in most of the produced brines. Traces of oil in the production water are only reported in one doublet. The co-produced gas degasses from the brines when the fluid pressure drops below the bubble point in the surface facilities. Typical gas-water ratios at the surface range between 0.5-1 m3 Nm3 gas per m3 produced water. Branch organisations and the Ministry of Economic affairs agreed that up to 3.6 Nm3 gas per m3 water and 5 m3 per day of co-produced oil is considered as inevitable and allowed co-production that does not require additional permitting.

The annual report is currently only available in Dutch under this link; an English version will soon be added to the nlog.nl website.

Production of heat by geothermal energy

We thank Cees Willems of the University of Glasgow for the article.